▎ 摘　　要

The development of thermal energy storage materials is essential to enhance the energy utilization. In particular, form-stable composite phase change materials (CPCMs) have attracted considerable interest because of their outstanding thermal properties and shape stability. However, their energy storage capacity decreases due to the fact that the filling of organic phase change components is limited by the pore diameter and void ratio of inorganic aerogels while following the common impregnation method. Herein, we present a simple and effective approach for fabricating form-stable CPCMs with in situ polyethylene glycol (PEG) filling in the 3D graphene oxide network side-to-side cross-linked by Ca2+. The filler content of PEG is maximized to 99.5 wt% because the side-to-side cross-linking mode greatly widens the void ratio of the 3D network. The prepared CPCMs exhibit high energy storage density as their melting enthalpy reaches 218.9 J g(-1), which is close to that of pure PEG6000; their thermal conductivity is enhanced by 63.0-87.7% compared to that of pure PEG. Meanwhile, the prepared materials have excellent thermal stability and shape stability.